1. Field of the Invention
The present invention relates to a projection display apparatus including an array light source in which plurality of solid state light sources are disposed in an array.
2. Description of the Related Art
Projection display apparatuses have heretofore been known, each of which includes a light valve (a liquid crystal panel or the like) modulating light emitted from a light source. A projection display apparatus projects light modulated by a light valve on a screen. Further, as a light source provided to a projection display apparatus, an attempt has been made to employ a solid state light source such as a laser diode or an LED.
Meanwhile, it is difficult to secure an amount of light necessary for a projection display apparatus only with a single solid state light source. For this reason, in a projection display apparatus, a plurality of solid state light sources are normally disposed in an array.
In the meantime, there is a case that a solid state light source deteriorates due to a change in ambient temperature of a solid state light source. Additionally, there is also a case that the solid state light source deteriorates with time. Thus, when the solid state light source deteriorates, variation occurs in an amount of light emitted from each of the solid state light sources disposed in an array. Accordingly, to prevent the variation of the amount of light emitted from each of the solid state light sources from occurring, it is necessary to detect the deterioration of the solid state light sources.
The following approach has also been disclosed for a case where a plurality of light sources are provided in such a projection display apparatus. In this approach, multiple sensors are provided to correspond respectively to the multiple light sources. Such approach is disclosed, for example, in Japanese Patent Application Publication No. Heisei 09-200662.
In the above-described projection display apparatus, multiple sensors are provided so as to correspond respectively to the multiple light sources. Hence, the number of the sensors increases with an increase in the number of the light sources, and this leads to an increase in the cost of the projection display apparatus. Moreover, with an increase in the number of the sensors, the controls of each of the sensors become complicated.
Further, in the projection display apparatus in which plurality of solid state light sources are disposed in an array, even when multiple sensors corresponding respectively to the plurality of solid state light sources are disposed, it is difficult to detect only light emitted from each of the solid state light sources.